The present invention relates to an improved blowout preventer packer which can be used for sealing against the exterior of different sizes of tubular members within a limited range as hereinafter set forth. Prior to the present invention there have been designs for allowing the blowout preventer packer to be actuated into sealing position which included expensive irising inserts or multiple component inserts which were tied together. While some of these prior art devices were capable of performing their design function, they were of complex structure and expensive to manufacture.
The B. C. Williams, III U.S. Pat. No. 4,229,012 discloses a variable bore packer for a ram-type blowout preventer in which the inserts embedded in the resilient packer were irising elements which each includes an upper plate, a lower plate and a rib connected between the upper and lower plates. Each of the plates is generally triangular in shape and designed to rotate as it moves inwardly with the resilient packer annulus so that the resilient material is supported when in sealing engagement with the exterior of a tubular string extending through the preventer. Also, a linkage structure is provided to allow the desired movement of the packer in sealing while maintaining its connection to the ram.
The G. R. Schaeper et al U.S. Pat. No. 4,579,314 discloses an annular type of blowout preventer in which the resilient annulus is provided with upper and lower insert plates embedded in the resilient annulus but is directed mainly to a side outlet in the body through which the annulus may be removed and replaced.
The R. K. LeRouax U.S. Pat. No. 3,915,426 discloses a ram-type variable bore blowout preventer in which a plurality of assemblies of pairs of spaced apart, radially extending plates, a single radially extending plate is held in position on one side of each pair of plates by a connector which is secured to the outer edges of each of the plates and has slots for the screws which connect to the pair of plates and such assemblies are positioned above and below the resilient packer to provide support and avoid extrusion of the resilient packer material when it is in sealing engagement with a tubular member and exposed to pressure below the preventer.